SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '020ca3c3671016934c787c318035ce5db57e357a72d918ca76d4f0ad436b683a' 
  AND token = 'OqEiRTSJ8FIJNs1xKvm7131xJ48ZdF51sBLTh6g1nho=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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