SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '29b9a4ca97b0c785669a9c9f22fcf528daac2cb03aaf50b66814ec1f134aa1c3' 
  AND token = 'lwSwSRc68tAh4ClHDVG/XUU7+AdzkDHA/mDTDWzbGr4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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