SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3c210a97ff42c3d2ba1203efd630eb0b1f56a250897d62cbfe14a32583904c68' 
  AND token = 'CluOr5mHrCy6JOlzlIgoRHN2eh/Ugc8w96z6mcau5+0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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