SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ac2632d83e2be95174091fecd5d59de1e78a704a6dbf1d22975eb3e459da4238' 
  AND token = 'zA5AEizScbNjIN0+QZIrxkcpSF5U6s2RkV5PEZyBxEg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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