SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aa4f847f57d94e1e0153ac0d885ce60d638ea39c74b973de57bc2353bcd4bc49' 
  AND token = 'gwsV4kQtWBuf4dVjqZ/mFxPDaiNYpwMVrqGC3SzmDks=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}