SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '81ae77ca7a58178b9b2edc252ac1d54fa40e9640d1eabdecd34e2de210ce6b70' 
  AND token = 'h3Oz9AJ2SSVogTJ7GrHBGtyFbi0AH09x1Zwa7G7rrXQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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