SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c717e285d4610fcb4205aa4512d0d318b8b288eda6cb8bd7ec4910f9e2e0ccfc' 
  AND token = 'OxwWJO5IQPmK2ST0odvC/NPKlfHi3+bPlzphbJNlXVM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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