SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2f98c5ef70edc3d448fa7a62ecca467bf197d54ea85661093057ac17d0f9b083' 
  AND token = 'BqtkGb/yqyjdh6walpjC+XGS31IK4pmWVgbVdvnbgT8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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