SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ad7daafc8fab756f5b721d5eb38659b458f7540950619e77b826396184188a8d' 
  AND token = 'Dsc+Cmk4LibvKlpsd4uMlxsY/h70jFAZdVU0vRuerNk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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