SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8dc25617a59be800d1b945e7f16c4610c81f06ee4967326abead261aea70474b' 
  AND token = 'LI/F7o56r0Jd0YtVsZbYVUWNK2jn5r6hSW5ve9Qucp0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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