SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bc3784cacf92fedfff5a28dd2660c7c33be30527a859d1e48be036e39660c6ea' 
  AND token = 'qsQw045aaHHspAWvscNxL9wE/F9dGJLyBSx3rop1nFw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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