SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bbd9fcd536ee698b6268f0f1bbc23ae65a7b09eaf9b942f7088901fb9bca0e5f' 
  AND token = 'dopGJfWTW7YXqyy4t74pJwDcBXXJN8qk9muPHyDGkAQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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