SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '77fd94c910b2431b8bc037e4f611c992151a31d6e50f601a213835572454465a' 
  AND token = 'LwtNiiNqlIf59qn8oEJ7Co1PLsSSMsZiQcNOr5rIPNw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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