SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '12b20a366be5ae6eb110dad0705de398327a1c65ce8bcec5ef7985bdf6084e1a' 
  AND token = '9XVukwn4n2bI2Ye3gkRqeYjbWc+hDXkOTYoWWP55k98=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}