SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '48c6174e908ce636e068fa196cbb995bf4b316763480d329b8a1603cc53da530' 
  AND token = 'OXZ6shrZIPYQsiZmM5jDnnt9YZvstkfmlei9HMSXHrM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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