SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '91a2d13d96b0a338873c55d743ea4f4fe867b482cf1ed589101bd098e35300ef' 
  AND token = 'aSnuSxMleP5kAn70Dy+kaRkbHHpjUke+/OeT+rAsqm8=' 
  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"
    }
  }
}