SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c717b07d90cce89e337142026e526278d0ccc1067c9139c13f9452245713b571' 
  AND token = 'poGOkR08LkR9wi4cB+tsZpSBrawBwlz6qleawZFh2Rs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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