SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5f2cb8e9f9783a4ee7deb1e3f2a0c036c5cf9d83dae4d638a4ca07103c8c4018' 
  AND token = 'DM0ESZz/fe0+FOUrzbTsXFEriZ8b1pUYSLTgiAybTFs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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