SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a8b9d3a2cb383ff1a7d3f61b4c43131803d29bb1e651d5b614307fc8ff575d64' 
  AND token = '5C1yGdK4IcoPi1gFwLkzeOpLEnt81p8yvgkZb5Qi29E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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