SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b0cf6626f8dcdf4290627d897205b00681f543f9224eb3b2fd4ac981a6a0c9b7' 
  AND token = 'bHGtMvZ2i+YpUVVPxtrthfCZCzcUqvNFq4R4GB119Xg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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