SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1519aad7c9fce772152b2eb9b7ad4bf87e9512ec3ca70206230e38d835b35784' 
  AND token = 'HShyiqnB1saPhlYOUwDrESlIEYjOZNLhlq+PgQ/end0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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