SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f0fd59f175fea74acf7a3762fd616dbfab542a37445f2c31296f8cb469664430' 
  AND token = 'jdTIJfrhuTHawXORvjRLta4sc6IL1W7d+McHCPtXU1c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}