SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '168f56eeb1de54b9850c295a3e95a8c443eca69a0ae447ccd3e4685b3432e51f' 
  AND token = 'gFf994woFxWslJgNe1Occ10l3ft/uRqv642pEcXqtCA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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