SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e78988d3d3c590b0d41655c8b8cc567ec8711c03d5ce0258c072ec3f8835747c' 
  AND token = 'yCiZ+yrCl9UGNR3JcNZDrNDfCbXTuADgnLKeImIy22g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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