SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '18b4f19213c5f9f4c5bcb4fda94969bd3eed5946b27a5b1c177f7cbcabfafbf3' 
  AND token = 'XMi1wfKNdsEcBJQQ/PRdwcfJWTewcQRu7YsHBj7pnik=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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