SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '97b58f0a8b416a11038cacb2e18a729c6953d00c7cf6390450432a3acde6da70' 
  AND token = 'Fz8FN2c+0W/wHTj/z8VACrtF5QCSE6RXngHRGLegmzI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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