SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8cabcef951fe0432cfec3c860de3ae219209ccb84f7f6e76921d012720e32bd1' 
  AND token = 'VdundR3SUsYPujDphcbhV73s+HLRpaIDtoz4jnURRLk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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