SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5c045ce8106be0c0e26b5952137d203ced58dda24dade8ebf0385fb38c699605' 
  AND token = 'TLItn/xy8XLib45vR08N29wtsDgeznELfgvOWOmxbOw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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