SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b1a467dee7a1aec9136fbf751a3cc4b0ca9a0fa7575393e69b34cdfc064b6fa5' 
  AND token = '9gqMTHGVEliwI1vpurDiyrcxWmYzvxnhqUsAlGYdSFU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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