SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fe56a504fe97e3284528fbfdaa3e9155872eb0c5e26c2d3004fd5f6405f3d5d3' 
  AND token = 'jwztL+GQz/dCmwLAWtnlSZH/bNSKKIxhz1EbwMzSvA4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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