SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f5baa87869dacca8ac079ffe5b2f82962143511340d73ac323b1e3eac2495ab6' 
  AND token = 'LvjM8Z3sEjFUsH4/Rm+N2o5hXqes0UVH0XMGZTHTKgI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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