SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5d1a803022974d3d5ca424263b5cc6174cfe1d2b4a8368ae9f7d9aa94234adcd' 
  AND token = 'uvxD8VcgSTGfHKJ0LpCa+uRN7+4/OmiPKjUqtLbWprQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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