SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '59b09b34d8fce1e462d04a290fe61e3391b4be82032d9e29a73519917a7d94a8' 
  AND token = 'lFaBCo+39y9JoEf6Mf90JDTXkoLSl2PMB/gbcEOgMik=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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