SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '92c203f5acff563c68cc3f89dce097a5649136282ceb3d1d5c3ef5150584c914' 
  AND token = 'wSjhSTfaFVq2GMHIIOckpZsvK5PZ7h63HeCMqRwYjbQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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