SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5cb41e083f381ab3f972e2b660dc5446af0d477a3c97527e2e5278d5cd3384e5' 
  AND token = 'naWPv5rlhpvSPYr6dk8+2UNSoZvpFU1/0WQH0JBI4T4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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