SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '69e231f95822d1d0e1e704c0417fe96be9f8d2fdef37fea27d45e4ddedde1208' 
  AND token = 'dQFq1P005Nt+Q6mjGglCAFrcc3tBh8Ht0Z2AAhmfcP0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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