SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9291078b97ffe118d44f28484cc203d9371f8f9421474348c07df2528501a45b' 
  AND token = 'XUQVsYLUPOkGWzy8A7b6Xzn1wZvsrQmFDyl6+S6PxR8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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