SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eb2fcd6c08e768101aa1d9e8d8664a99c18923733d420dde060b04f5ce1e58f8' 
  AND token = 'fX0+ZWALLuYTz82Gr3vbvlXjdFEmBhbze9T6mTUQ00s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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