SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fbd32476150a964aae953bd7276613ca3406933aa3adb804ea50794343c20ffc' 
  AND token = 'RUAaC7Xm4BYedzLyHf3zkOFNEH9gqiCSnc48urssVIc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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