SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5855628e5973b943fcf5b748da74b97e5e550822deff09a3414d5d2a5cdf8c70' 
  AND token = 'YJhCYJ7IyR2v7GkcYuyWs1ZOqtYXIAJQwvRDKsLcgzs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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