SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f7d347ec3ef3a0814314de83d86493a30a8bb240732b130d739a3bc2de4db67c' 
  AND token = 'imX7w1tt2pqQPPaBH7C0CMmzdbjCseZpQCubh4w4Hio=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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