SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1c646ded438ea38327fbf226db593406bf3a68ff42c2c880b5fffa9049e3701e' 
  AND token = 'uxOeEInY4o/H+gLgnVrhBevZna/dDEdlXZVRDTxuAY4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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