SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cb67a851773c06c0589334feb32bd9ccaa85be89918932fcda2f0e1eb9cce6ce' 
  AND token = '3AqDfSGk6zFCO6BE30aQcIHywpRsGe4nGAmvWHNRHXM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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