SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e471325598fdbe0011422c12060ad849f11a107893bb56d53c9444a699ba07aa' 
  AND token = 'f3Uh7s9cMVp2OHCP2j6FCXDo51hBJqZzuUOgNqhUqp0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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