SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '39c0a20953d29c94a84e182216f2ec4accae1409aba184d94e5b7be65b70d659' 
  AND token = 'aVub6rK3de+1+DkJkxij6IAyneMydPIzoQBM3FALSJM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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