SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e718826049f91315088df235534a62db38396645acb9c2bc7f319d402f11f02e' 
  AND token = 'PowqAuFqB/+lZ+gzlljtEY96zb+ZGhsfNx8m4tcoGYc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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