SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b474afa7ae4158bdc6f2d868ac2bbc9458b1199f0c4a4e1b37b6c29e28d629eb' 
  AND token = 'CIDOv7JNiQgq/DXr4jCAmSlQPw5gLDpYcuCRLExMUfA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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