SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '701b5f7f92b0965d1a0437b961eb74bf0c57f055b6be72ca846f7b34639a3e79' 
  AND token = '3R+jQaWdKHiZXxYdWaa/i9vPoWCNPJrQg9qQAokJw6M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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