SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '94fc735fbdfca46723491ad235c1424c548220fa848bcd3f8addb1d3de5d8b29' 
  AND token = 'gJTFCg6uBBO5f14EDzvgK8bIzYQHjrjB6EFHZWfMsBY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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