SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9c21f2c11cb190fd883a370bc70525773f14c8a871191f6fa4c6b98db39045c1' 
  AND token = '7KqboMN2D75m74ux5+BaqvW99mx2OzP/jFrEGqUKZr0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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