SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '928818abbd864833ff26ed1a34c6bcb625521b38349a784285635661088575fe' 
  AND token = 'NaCFIAj6IBvTsAEZoSctY0/t4mflmaCb6Yh37WYwISQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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