SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5220c5b7c775be7c13a50e5f54186d865e07276a237309658cdbb0329cd5c85c' 
  AND token = 'AGglbisygSW0Gu0QkF3g3mxPXUsp2anTyZnyzlQyVqs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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