SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9029ed2f5823f458f7270b48e902082650835b8e8abc288d272128c965f6e2e8' 
  AND token = 'usjqWjBDpjfZc0/Izr+LYEfIOYIeH1Wx65+kEtUHgKw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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