SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cf78ec8dea0a7f826e7357afb64fb9b0fb73df1c9936f899e94388a4b9717e52' 
  AND token = '5cXE+ethHsJvUIK/pQn9+rYgmqPrKi6A5dqzBEMhXdc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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