SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cfb55ff7c6038191eda4f0be53770dbd54890e9f486804d7a2c0e4b52231676c' 
  AND token = 'PLtRVQ6EOf/0KLudxznmORWB6GGIneSqR4OUTsd79SI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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