SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c68639dd8bd0332691fe0458d8be2c500c6145e02596b28dbad3ccab28becba4' 
  AND token = 'oaQp//qqgr8Z0nossX4ubNj9opXP8OXECZjEoRJrw3I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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