SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cc96448685ae1adff684776950969d167c90cadd6037aeadf9f27faa7dc04dcc' 
  AND token = '9JKYRrNd7sLilJT2dMujMoOVPHzdTO+RbYD7YORTjHw=' 
  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"
    }
  }
}