SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd276020030a5f3b69335dcb1512acdf178abb94e59a0197a7ce8185abf6c1f4f' 
  AND token = 'O7mJ2T+V1nIgX35FsCutf/Hq7sz3miMUIiG7Vv4OM/4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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