SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cd4f4a58686cafc1dd190d648d627c10c2ef3b98f24aebd5a989869609e51bb3' 
  AND token = 'ANR7Td+9rXrrQaEzt56JXfAbX5HrcdK9+/kjIYs0UNk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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