SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7071b66aa2e9ffe10c16feb6e3c7121797bf66fe8cbf0ffbbeff68448b28a15a' 
  AND token = 'xd1LhN/h0dhsEGNvCJZZQktGKhzy7UaxgspKBsn7eQI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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