SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '68fda11ac0678b3f0aef1571330e97218c937a27146340c72e837fb7273a8f46' 
  AND token = 'oETgZAG45GIek7FQCxkWXZzn2fxARwkTuHy4ILQ/rPo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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