SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f263e7e00acd2c44e07151de8c109f48fda15621ef4989f1c1e530c16b1da029' 
  AND token = 'buS6QSKNbMjPx0Z9iVuOlbAVpWUsNjmjPMibo3FRJ54=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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