SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '97dadf601b51bab6bfe8dfcc1f32db126752c51c72587f5d628a4c1c4e2da1ec' 
  AND token = 'b2RXCVMCH93F1OOvS6IKIQfrl4BzXCQTXCWKorbJHbY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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