SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ab747fbb18a74f7224a4738efa07e4792f4d49cba62ccab10492cf5ba2085cdb' 
  AND token = 'xUyplFIaSYX1Eh/8kMHRoXdImL3MYXrwIUJp3j7kANs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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