SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e7446f94baff0d98639d679201a8b33c958c7f2d606c628d32c5b70c843d464d' 
  AND token = 'YfCWJ8gmTvkzgYmT+6+wSbQqQlhmmgLcc2iTWLO8JGk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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