SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b66ec71ba3d3fdec2fe0d25edee45148bca005e9c8ba64333f0ddd7100bc3758' 
  AND token = '+CD6TYMHqWu2Jc0Q20+KzH8sTp2aqhSp6UJYFgdD3bs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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