SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f6eb365ad8d04a7c9860642504500f17de561a64eb76e75dfe7a9e44af5fc384' 
  AND token = 'M82IkVAuGhxHh1uzNFPcAxBWrdbqu/9wMWVMAfcj7e0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00129

JSON explain

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