SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7a1ddda2b831168313dd7cfda85d7208fae8fe0208175f0303ddcc83d72be08d' 
  AND token = 'O5cJc9SNS/DAjkhavz1WLMhb9c1Dush0azEWQyyXkWY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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