SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '32df39598768776d20b5aa3b202943da4384edb7b4349299d741fc142e0cf4b0' 
  AND token = '5JaYNmQXYBI5bVjChODLJPzKciUAyiM1GWtTHElZRho=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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