SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c5bdb60a22ccf2539fa436b37a909d231387b50e44eadf652342965bb79c931f' 
  AND token = '6FmFYwCHfWm2XwrcuU0lXoPslWAaPZLiDOb3RT9xnwI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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