SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd65793a8ec73fc742f07ac14199793fd441c0639a7e31068f119fd99d0bebcf2' 
  AND token = 'nfVMnYNcsh/Mxe9ziOs+CZTYJtk8vi0wK//WW7zroZQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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