SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '53c0270acc5c2826a89e43b4c272afe8bcb76071cbfc25a1509dbb31b4b3d687' 
  AND token = 'O2rjsl4K5x4wdldhrNVwxuoXSF2AcdpFoKlV8thqlPI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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