SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '03a30ce91eb51f7628592581603baa4f346e5d8f6bba08c6870b251dc27dd58b' 
  AND token = 'fzv7AwOPlwLGAd9ekJp8A8BiZO2h3KHJ21CqnjPmPTI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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